In the manufacture of semiconductor devices, multiple semiconductor devices (known as chips) are formed on a semiconductor wafer, and then divided into portions to separate the semiconductor devices from each other. Typically, before dividing the wafer, the electrical characteristics of each semiconductor device are tested.
A device known as a probe station (also known as a prober or probing apparatus) is used to test the semiconductor devices. Most probe stations have a movable support table known as a “wafer chuck” for supporting the semiconductor wafer under test. The probe station also has a head plate (also known as a head stage) that defines an original head plate aperture. The aperture supports a circular device known as a probe-card dish (also known as a probe-card ring or ring carrier), which in turn supports a probe card. The probe card has multiple probes usually in the form of elongated needles, which are configured to register with respective electrode pads of the semiconductor wafer supported on the wafer chuck. To test the semiconductor devices of the wafer, the wafer chuck brings the electrode pads of the wafer into contact with the probes. A separate piece of equipment, known as a tester, is lowered into mating position with respect to the probe station, and establishes an electrical circuit with the probe card and the wafer to enable testing of the wafer.
Generally, a number of guides and associated docking equipment pieces are needed to successfully dock a tester to a probe station. Probe stations are usually sold to semiconductor manufacturing facilities with this docking equipment already installed. Unfortunately, the docking equipment, which is typically installed by the probe station vendor or a secondary source, generally permits docking to a single make of tester. The installation of docking equipment to permit the use of a different tester with the probe station is referred to in the industry as “hardware swap-out” and results in extensive use of technician time and equipment down time.
Another issue facing semiconductor manufacturers is the lack of uniformity of head plate apertures among the various commercial lines of probe stations. The unfortunate result is that there is currently no known technique for mating a probe station having a first head-plate aperture size with a tester designed to mate with a probe station having a second head-plate aperture size.
Another issue facing semiconductor manufacturers is the ability of conventional probe cards to successfully establish electrical contact with each electrode pad of a wafer. In particular, as semiconductor devices become smaller and smaller due to advances in technology, probe cards with a greater density of probes are required. If the electrode pads of a large number of semiconductor devices are to be simultaneously brought into contact with corresponding probes, it is difficult to dispose the wafer such that the wafer is accurately parallel with the contact points of the probes. As a result, it is difficult to bring all of the electrode pads into contact with their respective probes, and to apply uniform pressure to the contact points of the probes.
Accordingly, there exists a need for improved systems for testing semiconductor devices.